Uncaught TypeError: this.XXXXX is not a function

See if you call the method is not in the sentence and not a function in the method,
such as

A（）{
    a(){
		this.B
	}
}
B(){

}

A and B are the same level, this can not be a used, this refers to a straight of A
so

A（）{
	var that = this
    a(){
		that.B
	}
}
B(){

}